Method and program for file information write processing

Abstract

The file information write processing method according to the present invention is a file information write processing method wherein a computer executes a process for outputting instruction corresponding to a file information write instruction from an application to a device driver, wherein: searching clusters which are empty areas within an actual data area of a memory unit of the computer, and obtaining the search result; if clusters which are empty areas exist, writing information to overwrite to one or more clusters within the actual data area of the memory unit which is a target of the write instruction from the application, to the clusters which are empty areas; and freeing clusters which were to be overwritten by the information written to the empty area clusters.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2004-375074, filed in Dec. 12, 2004, the entire contents of which are incorporated herein by reference. FIELD OF THE INVENTION [0002] The present invention relates to a processing method for writing file information and program thereof. BACKGROUND OF THE INVENTION [0003] File access within a computer system is realized through a combination of three programs: application; file system (middleware); and device driver. Here, application refers to various application programs such as word processors and CAD software. Device driver refers to a control program which performs read / write on each area within a (nonvolatile) secondary memory, such as magnetic disks and flash memory, wherein stored contents are retained even when power is tuned off. File system (middleware), which is provided between application and device driver, perfo...

AI Technical Summary

Benefits of technology

[0034] The objective of the present invention is to provide a write processing method and program which enables shortening of the period wherein there is risk of data damage when power supply interruption and the like occur.

[0036] Here, since data which should be overwritten to the cluster specified as the write target is written to the cluster of the empty area within the actual data area which has been searched and obtained, if as many of these clusters which are empty areas as there are clusters which are write targets are secured, the data to be overwritten can be written to this empty area cluster all at once. In this case, by comparing this to the conventional example wherein data is directly overwritten to this write target cluster, it is possible to eliminate the risk of storing incomplete data within the actual data area due to the power supply interruption during the data overwrite, so when a power supply interruption and the like occur, the period wherein there is risk of data damage is shortened. Data to be overwritten refers to update information, or in other words, “Data New”(shown in FIGS. 15 to 18 as Data2 New, Data3 New, and Data4 New).

[0038] Here, the change or the generation of the directory entry of the file of the destination of the movement is made so as to link to the actual data in the file of the source of the movement in a state wherein the link between the directory entry of the file of the source of the movement and the actual data of the file of the source of the movement is kept, the period wherein the information of the file of the source of the movement only exists in the primary memory, as in the conventional example, is eliminated, and the period wherein risk of data damage exists, when power supply interruption and the like occurs, can be shortened.

[0039] According to the present invention, because data which should be overwritten to the cluster specified as write target is written to the cluster of the empty area within the actual data area which has been searched and obtained, data which should be overwritten can be written to the empty area cluster all at once, when as many of these clusters which are empty areas as there are clusters which correspond to the data comprised in the write instruction from the application are secured. In this case, by comparing this to the conventional example wherein data is directly overwritten to this write target cluster, it is possible to eliminate the risk of storing incomplete data within the actual data area due to the power supply interruption during data overwrite, so when a power supply interruption and the like occur, the period wherein there is risk of data damage is shortened.

[0040] In addition, according to the present invention, the change or the generation of the directory entry of the file of the destination of the movement is made so as to link to the actual data in the file of the source of the movement in a state wherein the link between the directory entry of the file of the source of the movement and the actual data of the file of the source of the movement is kept, the period wherein the information of the file of the source of the movement only exists in the primary memory, as in the conventional example, is eliminated, and the period wherein risk of data damage exists, when power supply interruption and the like occurs, can be shortened.

Problems solved by technology

In other words, it is a period wherein there is risk of data damage.

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